Reaction mechanism and electrochemical characterization of a Sn-Co-C composite anode for Li-ion batteries

A Sn-Co-C composite is prepared by mechanochemical synthesis using tin powder and a cobalt-carbon composite through the pyrolysis of Co (III)-acetylacetonate. The composite is studied as an anode material for Li secondary batteries. The reaction mechanism is investigated using various analytical techniques. Although the composite is initially composed of Co₃Sn₂ as the major phase and CoSn₂ as the minor one, the Co₃Sn₂ transformed into CoSn₂ during the second cycle and remained in this form throughout the following cycles. The Sn-Co-C composite shows an excellent capacity retention of 435 mAh g⁻¹ over 100 cycles.